TamTam roundup.

Hal Murray hmurray at megapathdsl.net
Sun May 20 18:52:13 EDT 2007

> If any magic name has to be used, try pool.ntp.org. Maybe not nice,
> but better than a newly invented name.

If anybody isn't already familiar with the UWisc/Netgear story, here's the 
  Flawed Routers Flood University of Wisconsin Internet Time Server
I call it required reading for anybody interested in networking.

Unless you have permission from the owner, it's a really really bad idea to 
wire a name or IP address into any system and them ship zillions of those 

Even if you do have permission, you should probably use a name or address of 
your own in order to avoid an external dependency on some infrastructure that 
you don't have any control over.

In the OLPC case, there is another reason for not using the pool.  We don't 
want all the NTP traffic from each XO going out over the school-to-world 
link.  On top of that, a random collection of servers scattered around the 
globe won't provide very good time.

I think ntpd can provide good enough time for tamtam to use absolute times.  
That's assuming the XOs are synced to a local school server.  (That's not a 
promise, just my best estimate.  We'll know more when somebody gets some ping 
data from a reasonable size mesh.)

> There is a standard for time serving via DHCP.
That's not time serving itself.  That's distributing the IP Address of a time 

ntpd doesn't support getting the server address directly via DHCP.

gentoo has a NTP wiki page that includes using DHCP
Basically, they are rewriting ntp.conf on the fly

None of the systems I've worked with have done that.

ntpd has a couple of multicast/broadcast modes.  They may be appropriate.  I've never worked with them.

How are the XOs going to find their backup server?

These are my opinions, not necessarily my employer's.  I hate spam.

More information about the Devel mailing list